<?php
/**
 * @version V4.93 10 Oct 2006 (c) 2000-2009 John Lim (jlim#natsoft.com). All rights reserved.
 * Released under both BSD license and Lesser GPL library license.
 * Whenever there is any discrepancy between the two licenses,
 * the BSD license will take precedence.
 *
 * Set tabs to 4 for best viewing.
 *
 */

/*
 * Concept from daniel.lucazeau@ajornet.com.
 *
 * @param db		Adodb database connection
 * @param tables	List of tables to join
 * @rowfields		List of fields to display on each row
 * @colfield		Pivot field to slice and display in columns, if we want to calculate
 *						ranges, we pass in an array (see example2)
 * @where			Where clause. Optional.
 * @aggfield		This is the field to sum. Optional.
 *						Since 2.3.1, if you can use your own aggregate function
 *						instead of SUM, eg. $aggfield = 'fieldname'; $aggfn = 'AVG';
 * @sumlabel		Prefix to display in sum columns. Optional.
 * @aggfn			Aggregate function to use (could be AVG, SUM, COUNT)
 * @showcount		Show count of records
 *
 * @returns			Sql generated
 */

function PivotTableSQL(&$db,$tables,$rowfields,$colfield, $where=false,
$aggfield = false,$sumlabel='Sum ',$aggfn ='SUM', $showcount = true)
{
    if ($aggfield) $hidecnt = true;
    else $hidecnt = false;

    $iif = strpos($db->databaseType,'access') !== false;
    // note - vfp 6 still doesn' work even with IIF enabled || $db->databaseType == 'vfp';

    //$hidecnt = false;

    if ($where) $where = "\nWHERE $where";
    if (!is_array($colfield)) $colarr = $db->GetCol("select distinct $colfield from $tables $where order by 1");
    if (!$aggfield) $hidecnt = false;

    $sel = "$rowfields, ";
    if (is_array($colfield)) {
        foreach ($colfield as $k => $v) {
            $k = trim($k);
            if (!$hidecnt) {
                $sel .= $iif ?
					"\n\t$aggfn(IIF($v,1,0)) AS \"$k\", "
                :
					"\n\t$aggfn(CASE WHEN $v THEN 1 ELSE 0 END) AS \"$k\", ";
            }
            if ($aggfield) {
                $sel .= $iif ?
					"\n\t$aggfn(IIF($v,$aggfield,0)) AS \"$sumlabel$k\", "
                :
					"\n\t$aggfn(CASE WHEN $v THEN $aggfield ELSE 0 END) AS \"$sumlabel$k\", ";
            }
        }
    } else {
        foreach ($colarr as $v) {
            if (!is_numeric($v)) $vq = $db->qstr($v);
            else $vq = $v;
            $v = trim($v);
            if (strlen($v) == 0	) $v = 'null';
            if (!$hidecnt) {
                $sel .= $iif ?
					"\n\t$aggfn(IIF($colfield=$vq,1,0)) AS \"$v\", "
                :
					"\n\t$aggfn(CASE WHEN $colfield=$vq THEN 1 ELSE 0 END) AS \"$v\", ";
            }
            if ($aggfield) {
                if ($hidecnt) $label = $v;
                else $label = "{$v}_$aggfield";
                $sel .= $iif ?
					"\n\t$aggfn(IIF($colfield=$vq,$aggfield,0)) AS \"$label\", "
                :
					"\n\t$aggfn(CASE WHEN $colfield=$vq THEN $aggfield ELSE 0 END) AS \"$label\", ";
            }
        }
    }
    if ($aggfield && $aggfield != '1'){
        $agg = "$aggfn($aggfield)";
        $sel .= "\n\t$agg as \"$sumlabel$aggfield\", ";
    }

    if ($showcount)
    $sel .= "\n\tSUM(1) as Total";
    else
    $sel = substr($sel,0,strlen($sel)-2);


    // Strip aliases
    $rowfields = preg_replace('/ AS (\w+)/i', '', $rowfields);

    $sql = "SELECT $sel \nFROM $tables $where \nGROUP BY $rowfields";

    return $sql;
}

/* EXAMPLES USING MS NORTHWIND DATABASE */
if (0) {

    # example1
    #
    # Query the main "product" table
    # Set the rows to CompanyName and QuantityPerUnit
    # and the columns to the Categories
    # and define the joins to link to lookup tables
    # "categories" and "suppliers"
    #

    $sql = PivotTableSQL(
    $gDB,  											# adodb connection
 	'products p ,categories c ,suppliers s',  		# tables
	'CompanyName,QuantityPerUnit',					# row fields
	'CategoryName',									# column fields 
	'p.CategoryID = c.CategoryID and s.SupplierID= p.SupplierID' # joins/where
    );
    print "<pre>$sql";
    $rs = $gDB->Execute($sql);
    rs2html($rs);

    /*
     Generated SQL:

     SELECT CompanyName,QuantityPerUnit,
     SUM(CASE WHEN CategoryName='Beverages' THEN 1 ELSE 0 END) AS "Beverages",
     SUM(CASE WHEN CategoryName='Condiments' THEN 1 ELSE 0 END) AS "Condiments",
     SUM(CASE WHEN CategoryName='Confections' THEN 1 ELSE 0 END) AS "Confections",
     SUM(CASE WHEN CategoryName='Dairy Products' THEN 1 ELSE 0 END) AS "Dairy Products",
     SUM(CASE WHEN CategoryName='Grains/Cereals' THEN 1 ELSE 0 END) AS "Grains/Cereals",
     SUM(CASE WHEN CategoryName='Meat/Poultry' THEN 1 ELSE 0 END) AS "Meat/Poultry",
     SUM(CASE WHEN CategoryName='Produce' THEN 1 ELSE 0 END) AS "Produce",
     SUM(CASE WHEN CategoryName='Seafood' THEN 1 ELSE 0 END) AS "Seafood",
     SUM(1) as Total
     FROM products p ,categories c ,suppliers s  WHERE p.CategoryID = c.CategoryID and s.SupplierID= p.SupplierID
     GROUP BY CompanyName,QuantityPerUnit
     */
    //=====================================================================

    # example2
    #
    # Query the main "product" table
    # Set the rows to CompanyName and QuantityPerUnit
    # and the columns to the UnitsInStock for diiferent ranges
    # and define the joins to link to lookup tables
    # "categories" and "suppliers"
    #
    $sql = PivotTableSQL(
    $gDB,										# adodb connection
 	'products p ,categories c ,suppliers s',	# tables
	'CompanyName,QuantityPerUnit',				# row fields
    # column ranges
    array(
' 0 ' => 'UnitsInStock <= 0',
"1 to 5" => '0 < UnitsInStock and UnitsInStock <= 5',
"6 to 10" => '5 < UnitsInStock and UnitsInStock <= 10',
"11 to 15"  => '10 < UnitsInStock and UnitsInStock <= 15',
"16+" =>'15 < UnitsInStock'
),
	' p.CategoryID = c.CategoryID and s.SupplierID= p.SupplierID', # joins/where
	'UnitsInStock', 							# sum this field
	'Sum'										# sum label prefix
);
print "<pre>$sql";
$rs = $gDB->Execute($sql);
rs2html($rs);
/*
 Generated SQL:

 SELECT CompanyName,QuantityPerUnit,
 SUM(CASE WHEN UnitsInStock <= 0 THEN UnitsInStock ELSE 0 END) AS "Sum  0 ",
 SUM(CASE WHEN 0 < UnitsInStock and UnitsInStock <= 5 THEN UnitsInStock ELSE 0 END) AS "Sum 1 to 5",
 SUM(CASE WHEN 5 < UnitsInStock and UnitsInStock <= 10 THEN UnitsInStock ELSE 0 END) AS "Sum 6 to 10",
 SUM(CASE WHEN 10 < UnitsInStock and UnitsInStock <= 15 THEN UnitsInStock ELSE 0 END) AS "Sum 11 to 15",
 SUM(CASE WHEN 15 < UnitsInStock THEN UnitsInStock ELSE 0 END) AS "Sum 16+",
 SUM(UnitsInStock) AS "Sum UnitsInStock",
 SUM(1) as Total
 FROM products p ,categories c ,suppliers s  WHERE  p.CategoryID = c.CategoryID and s.SupplierID= p.SupplierID
 GROUP BY CompanyName,QuantityPerUnit
 */
}
?>